Attachment-plug.



R. S. BLAKE.

ATTACHMENT PLUG. Arrmrm'mpfi 11.21) SEPT. 2, mm.

zwerzaim s rens era-rear orn te.

ROBERT S. BLAKE, OF CHICAGO, ILLINOES, ASSIGNOR TO FETDEEAL ELECTRIC(IOIHPAN'E', 0E CHICAGO, ILLINOIS, A GOR'EORATION OF ILLINOIS.

AITACHMENT-PILUG.

Specification of Letters Patent.

Patented Dec. 26, li ht.

Application filed September 2, 1910. Seriald lo. 5539,2453.

To all whom it may concern:

Be it known that 1, ROBERT S. BLAKE, a citizen of the United States, anda. resident of Chicago, in the county of Cook and State of lllinois,have invented certain new and useful Improvements in Attachment-Plugs;and I do hereby declare that the following i is a full, clear, and exactdescription thereof, reference being had to the accompanying f drawings.and to the letters of reference marked thereon, which form a. part ofthis specification.

This invention relates to an improvement in attachment plugs adapted tobe inserted into a wall socket or other electrical contact l receptaclefor connecting electric conductors, and consists of the mattershereinafter described and more particularly pointed out in K theappended claims.

The improved attachment plug is of the type that may be caused to engageWithin the internally screw-threaded shell of a socket without screwingit into said socket i and includes a collapsible, externally threadedshell which may he inserted into the socket while collapsed; means forexpanding the shell after it has been thus inserted, to cause its threadto engage with the thread of the internally threaded shell of thesocket; and means for locking it in i that position.

In the drawings :-Figure l is a perspective View of the attachment plugas it appears before it is inserted into the well i socket. dis alongitudinal central sec 3 tion of the plug attachment shown with itsshell GXPHIKlQd and engaged with the inter 1 na-lly threaded shell of a.wall socket. Fig. is a similar section showing the parts as 3 they arewhen the shell is collapsed and the plug attachment partially Withdrawnfrom the socket. Fig. 4: is a cross-section through the plug attachmenton the line d-4 of Fig. 2. Fig. 5 is a. cross-section through Fig. 3 onthe line 5-5 thereof. Fig. 6 is a crossscction through Fig. 2 on theline G6 thereof. Fig. Tis a cross-section through the plug attachment onthe line 77 of Fig. 2. Fig. 8 is a cross-section through the plug rattachment on the line S% of Fig. 2.

My improved plug attachment embraces a plug A; a. base l3; and a cap C.The plug A is preferably made of porcelain and is bored centrally toprovide a longitudinal aperture (1 which is larger in diameter at its 1lower end to receive a tube D, and of smaller diameter at its upper endto receive a bolt E which is threaded into the upper end of the saidtube D. The head 6 of said bolt forms the central contact of the plugattachment.

1 The plug has a reduced part A at its rear end to which is secured across-bar F, preft erably made of fiber. The tube D projects from therear of the plug and is there square in cross-section, as shown at d,Where it engages Within the square aperture f in the cross-bar l Thisconstruction prevents angular movement of the cross-bar. The end of thetube D is closed being provided with a flanged head al which holds thecrossbar against the end of the plug A.

The hose B consists of an annular block of. porcelain or fiberexternally threaded near its bottom to receive the internally threadedflange c of the cap C. To the bottom. of said base is secured aterminalplate 7 to which is connected one of the electric conductors G and intowhich is screwthreaded the end of a bolt G Said bolt passes through acentral aperture formed through the base B and through an aperture inthe closed end of the tube D and has a head .(l located within the tubeD and adapted to slide therein. A coiled spring H bears between thelower end of the bolt E and the head of the bolt G and serves toelectrically connect them. To the top of the base B is secured a fiatmetallic ring J which surrounds the reduced end A of the plug andprojects inwardly beyond the ends of the cross-bar F. Said ring issecured to the hose by means of longitudinal bolts j which extendthrough suitable apertures in the base and are threaded into said ring.One of said bolts passes through a terminal plate It to which isconnected a conductor K.

L is a cone member secured to the top of the base B. As shown herein, itconsists of a tubular shell provided with an in-turned flange Z at itsupper end which engages against the body of the plug A and at its basewith a cone Z". T he lower edges of the cone embrace the ring J to whichit is soldered or secured in any other convenient manner.

At the upper end of the plug is formed an annular shoulder M againstwhich rests a flange m of a split threaded conta ct shell N. 'lheloweredges of said shell are adapted to be brought into engagement with thecone Z Said flange m of the shell is provided with diametrically opposednotches m which are adaptedto be engaged by radial shoulders m on theplug A which thus prevent the rotation of said shell with reference tosaid plug. Two sections N, N of said shell are adapted to collapsetoward the plug A A coiled spring P bears between the upper flanged endof the cone member L and thefiange m of the contact shell N and thusholds said shell in place, and at the same time tends to hold the shelland cone apart, so that the shell sections N N will be collapsed on theplug A.

.In the rin J are formed diametrically opposed note es J through whichthe ends- 0 the'cross-bar F are adapted to pass when the base is rotatedinto position to bring saidnotches in line with the end of said bar.

The operation. of the device is as follows :Consider the plug-with theparts as illustrated in Fig. 1. The cap C is grasped and the attachmentas a whole is pushed into the socket, the shell N being collapsed, asclearly to be seen in Fig. 3. When the end of the plug reaches the limitof its movement, the further movement of'the base and I cap causes theconical base of the cone member to expand the shell and this movement ofthe base with reference to. the plug forces the ring J beyond thecross-bar F, the notches J in said ring permitting this movement. Thecap'and base are then rotated or given a part turn which brin thenotches J, J of the ring to one side 0 the ends of the crossbar (asclearly to be seen in Fig. 4),.so that the ring engages against saidcross-bar and locks theparts in expanded relation. To remove the plugattachment the operation is reversed.

I'clai'm as my invention 1. An attachment plug comprising a plug member,a shell contact member surrounding said plug member and having sectionswhich are normally collapsed on said plug member, a cone-member movableon said.

plug -.member within said shell member, a spring surrounding said plugmember. and interposed between said shell member and said conemember andbeing adapted to resist the movement of said cone-member Within saidshell. member when the cone member is moved toward a position to ex-'pand said shell member, and means for locking said cone-member againstlongitudinal movement on-said plug member when said cone-member has beenbrought into position to expand said shell member.

2. An attachment plug comprising a plug member, a shell contact membersurrounding said plug member and-having sections which are normallycollapsed on said member, a cone-member adapted to expand said shellmember, said cone member being longitudinally movable on said plugmember within said shell ,mg base and said plug member, means interposedbetween said cone-member and said. shell member adapted to resist theniovement of said cone-member within said shell member when thecone-member is moved toward-the position for expanding said shellmember, a base to which said cone-member is secured, a cross-barfsecured to the outer end of said plug member, a locking member carriedby said base adapted to interlock with said cross-bar, and mechanicalconnections between said base and plug member adapted to permit limitedlongitudinal and rotatable movement of said base with reference to saidplug member.

3. An attachment plug comprising a plug member, a normally collapsedshell contact member surrounding said plug member, a cone-member movablelongitudinally on said plug member within said shell member, yieldingmeans interposed between said cone-member and said shell memberadaptedto yield when the cone-member is moved to-- Ward a position to expandsaid shell member, a base to which said cone-member is secured,mechanical connections between said base and said plug member adapted topermit said base to have both longitudinal and rotatable movement withreference to said plug member, a crossbar at the outer end of said plugmember, and a fixed laterally projecting part carried by. said base,said cross-bar being adapted to engage beneath said fixed part carriedby said base.

4. An attachment plug comprising a plug -member of insulating material,said plug having an annular flange at its upper end, a shell contactmember surrounding said plug and-having an inturned flange engagedbeneath said plug flange, said shell contact member having long1tudinalsections normally collapsed toward said plug, and said shell flange andplug flange having interlocking parts to prevent rotation of said shell,a metallic cone-member embracing a hollow cylindric member having aninturned flange bearing against said plug and a hollow conical baseadapted to expand the sections of said shell, a spring interposedbetween said cone member and the flange of said shell contact member, aninsulating base to which said cone member is secured, and interlockingparts carried by said insulatmember adapted to lock the parts inexpanded relation.

5. In' an attachment plug comprising a plug member, aenormally collapsedshell contact member surrounding said plug member, ametallic cone-membermovable on said plug member spring surrounding said plug member andinterposed between said cone-member and said shell member adapted to,resist the movement of said cone-member within said shell member whensaid cone-member is 1 0 within said shell member, a

moved into position to expand said shell member, an insulating basemovable longitudinally of the plug member with said cone-member, anapertured dislrsecured to the top of said insulating base andmechanically and electrically connected to said conemember, saidinsulating base having a central aperture of greater diameter than theaperture in said disk, said plug member having a reduced end adapted topass through the aperture in said disk, and a cross-bar secured to thereduced end of said plug member adapted to pass through the aperture insaid insulating base, said disk having notches to permit the passage ofsaid cross-bar.

6. In an attachment plug embracing a plug member, a shell contact membersurrounding said plug member and having longitudinal sections normallycollapsed on said plug member, a cone-member longitudinally movable onsaid plug member within said shell member, a spring surrounding saidplug member and interposed between said cone-member and said shellmember, a base to which said cone-member is secured,

said plug member having a reduced end and a central longitudinalaperture of different diameters, a tube located in the lower largeraperture, a bolt located in the upper smaller aperture and threaded intothe. upper end of said tube, a second bolt having a head located in saidtube and a shank projecting below said tube, a spring interposed betweenthe lower end of the first bolt and the head of the second bolt, across-bar provided with a polygonal recess, said tube projecting belowthe end of the reduced part of the plug into the recess of saidcross-bar and having a cross-section adapted to [it said recess, and aflanged closure at the end of said tube adapted to rigidly secure saidcross-bar to said plug.

In testimony that I claim the foregoing as my invention I alfix mysignature in the presence of two witnesses, this th day of August A. D.1910.

ROBERT S. BLAKE.

Witnesses C CLARENCE PooLE, GEORGE E. lVILKINs.

